PS3 was mentioned as a release platform in the Project 510 interview and never since. Xbox360 and Xbox One haven't been mentioned at all, but may appear at a later time.

And if you're wondering why we haven't heard anything about the Xbox, then GamingBolt has your answer:

Quote:

Originally Posted by GamingBolt (August 24, 2014)

Alen Ladavac also revealed why there is no Xbox One version and the reason is rather surprising. They haven’t received Xbox One development kits which is baffling since Croteam are a reputed developer having worked on the Serious Sam series. “In the nutshell – we still weren’t able to get our hands on development kits for Xbox One. Without that, it’s hard to develop for it. ,” Alen said.

Release Date
The official release is December 11, 2014 on PC, mac and linux.
PS3 and Android (nVidia Shield Tablet and other tablets with Tegra K1) will follow in Q1 2015.

Game Length
The game is said to have over 120 puzzles.

Expected playtime has not been announced, but it will depend highly on how well the player does at the puzzles and how much the player chooses to explore the story and the game world.

Other Info
As part of the promotion of The Talos Principle, Croteam released a free puzzle game called Sigils of Elohim. The game contains a set of tetris-like puzzles for the player to solve. Solving the puzzles with unlock itmes for the player in The Talos Principle.

More puzzles (and unlocks) will be released for Sigils of Elohim through updates as the release of The Talos Principle nears. The game is available on Steam, iOS and Android.